U.S. patent application number 16/658801 was filed with the patent office on 2020-02-13 for seat with detector.
The applicant listed for this patent is TS TECH CO., LTD.. Invention is credited to Shinji Sugiyama.
Application Number | 20200047640 16/658801 |
Document ID | / |
Family ID | 57005052 |
Filed Date | 2020-02-13 |
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United States Patent
Application |
20200047640 |
Kind Code |
A1 |
Sugiyama; Shinji |
February 13, 2020 |
SEAT WITH DETECTOR
Abstract
A seat is configured to suitably restrain a warping of a
connecting portion in a signal transmission path, when the
connecting portion is disposed inside a through hole provided in a
pad member of the seat. The seat includes: a pressure sensor that
detects a seating pressure of a seat occupant; a leading wire of
the transmission path that extends from the pressure sensor; a
cable of the transmission path that extends from an electronic
control unit for a signal output from the pressure sensor; a warp
restraining member that restrains a warping of a connecting portion
of the leading wire and the cable; and a through hole formed in a
pad member of the seat, from one end to another end in the
thickness direction of the pad member. The warp restraining member
is inserted into the through hole to thereby pass the transmission
path through the through hole.
Inventors: |
Sugiyama; Shinji; (Tochigi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TS TECH CO., LTD. |
Asaka-shi |
|
JP |
|
|
Family ID: |
57005052 |
Appl. No.: |
16/658801 |
Filed: |
October 21, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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15561777 |
Sep 26, 2017 |
10449874 |
|
|
PCT/JP2016/059637 |
Mar 25, 2016 |
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16658801 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60N 2/58 20130101; B60N
2/5816 20130101; B60N 2002/0268 20130101; B60N 2/90 20180201; B60N
2/002 20130101; B60N 2/70 20130101 |
International
Class: |
B60N 2/00 20060101
B60N002/00; B60N 2/58 20060101 B60N002/58; B60N 2/70 20060101
B60N002/70; B60N 2/90 20060101 B60N002/90 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 27, 2015 |
JP |
2015-067209 |
Mar 27, 2015 |
JP |
2015-067210 |
Mar 27, 2015 |
JP |
2015-067211 |
Claims
1. A seat comprising: a detector which detects a target value that
changes when a seat occupant is seated on the seat; a first
transmission path forming portion that extends from the detector
and forms a portion of a transmission path for a signal output when
the detector has detected the target value; a second transmission
path forming portion which forms a portion of the transmission path
and extends from a signal receiving unit which receives the signal;
a warp restraining member configured to restrain a warping of a
connecting portion of the transmission path that connects a first
portion formed with the first transmission path forming portion and
a second portion formed with the second transmission path forming
portion; and a through hole that is formed in a pad member provided
inside the seat and that extends from one end of the pad member to
another end of the pad member in a thickness direction of the pad
member; wherein the warp restraining member is inserted into the
through hole to thereby pass the transmission path through the
through hole.
2. The seat according to claim 1, wherein: the connecting portion
comprises a fastening member that fastens respective end portions
of both of the first transmission path forming portion and the
second transmission path forming portion; and the fastening member
and the end portions are fixed onto an outer surface of the warp
restraining member to restrain the warping of the connecting
portion.
3. The seat according to claim 2, wherein the warp restraining
member comprises a resin material and the outer surface is
elliptically curved.
4. The seat according to claim 2, wherein: the seat comprises
multiple detectors that include the detector; the first
transmission path forming portion, the second transmission path
forming portion, and the fastening member are provided to each of
the multiple detectors; the seat further comprises a holder film
attached to each of the first transmission path forming portion,
the second transmission path forming portion, and the fastening
member of each of the multiple detectors, and configured to hold
each of the same; and the warp restraining member restrains the
warping of the connecting portion to fix a portion of the holder
film which is attached to the fastening member and the end portions
onto the outer surface, in a state wound around the warp
restraining member along the outer surface.
5. The seat according to claim 4, wherein: the holder film
comprises a first film portion and a second film portion adjacent
to each other and having different widths; the first film portion
having a larger width, being attached to the fastening member and
the end portions, and being wound around the warp restraining
member along the outer surface; the second film portion a narrower
width and being attached to the first transmission path forming
portion of each of the multiple detectors; the warp restraining
member comprises a flange portion having a part notched in an end
portion of the warp restraining member; and in a state that the
first film portion is wound around the warp restraining member, the
second film portion comes into a recess portion which is formed by
notching a part of the flange portion.
6. The seat according to claim 1, wherein: the warp restraining
member is inserted in the through hole, in a state along a partial
region of an inner wall of the through hole; and the partial region
of the inner wall of the through hole forms a gradient face.
7. The seat according to claim 6, wherein the partial region of the
inner wall of the through hole forms the gradient face to be
declined such that out of both ends of the partial region in the
thickness direction, an end of the partial region nearer to the
detector is positioned forward relative to an end of the partial
region farther away from the detector.
8. The seat according to claim 1, wherein: the connecting portion
comprises a fastening member that fastens respective end portions
of both of the first transmission path forming portion and the
second transmission path forming portion; the seat comprises
multiple detectors that include the detector and are provided in
positions different from each other; the multiple detectors
comprise a first detector and a second detector which are arranged
side by side in a state spaced from each other in a seat width
direction; each of the multiple detectors comprises the first
transmission path forming portion, the second transmission path
forming portion, and the fastening member; the seat further
comprises a holder film attached to each of the first transmission
path forming portion, the second transmission path forming portion,
and the fastening member of each of the multiple detectors, and
configured to hold each of the same; in the holder film, a portion
sandwiched between the first detector and the second detector in
the seat width direction comprises a first extending portion which
is in an outer side in the seat width direction and extends along
the seat width direction, and a second extending portion which is
in an inner side in the seat width direction and extends along the
seat width direction at a rear-position relative to the first
extending portion; and the through hole is formed so as to be
positioned forward of the second extending portion in the pad
member.
9. The seat according to claim 8, wherein the through hole is
formed such that a rear end of the through hole is positioned
rearward relative to a fore-end of the first extending portion, in
a seat front to back direction.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation application of U.S.
patent application Ser. No. 15/561,777, filed Sep. 26, 2017, now
U.S. Pat. No. 10,449,874, which is the National Stage Entry
application of PCT Application No. PCT/JP2016/059637, filed Mar.
25, 2016, which claims the priority benefit of Japanese Patent
Application Nos. JP 2015-067209, JP 2015-067210, and JP
2015-067211, all filed Mar. 27, 2015, the contents being
incorporated herein by reference.
BACKGROUND
[0002] The present disclosure relates to a seat with a detector,
specifically, a seat comprising a detector which detects a target
value that changes when a seat occupant is seated on a seat.
[0003] Seats comprising a detector such as a sensor have already
been known. Examples of known seats include those comprising a
pressure sensor which detects a pressure applied to each portion of
a seat face (seating pressure), when a seat occupant is seated on
the seat. In such seats, a pressure sensor is generally disposed
directly under a seating face. On the other hand, a device (signal
receiving unit) which receives a signal which is output when a
pressure sensor has detected a seating pressure is disposed in a
position away from the pressure sensor. For example, a case is
supposed where the signal receiving unit is disposed in the back
face side (opposite side of the seating face) of a pad member that
forms the seating face. In such a case, for such a circumstance
that a transmission path for signals output from the pressure
sensor is shortened as much as possible, it is possible to employ a
structure in which a through hole is made in the pad member, and a
transmission path is passed through the through hole, as described
in Japanese Patent Publication JP 2013-95373.
[0004] In this connection, the transmission path is separated into
a portion extending from the pressure sensor and a portion
extending from the signal receiving unit, in some cases. In such
cases, there should be a connecting portion which connects the two
portions constituting the transmission path. It is supposed that
the connecting portion is disposed inside the through hole
described above, for a purpose of avoiding being damaged from
interfering with a peripheral member, or the like. However, even if
the connecting portion is disposed inside the through hole, when a
relatively large load is applied around the through hole, there is
a risk that the load may be transmitted to the connecting portion
to warp and damage the connecting portion.
SUMMARY
[0005] Thus, the present disclosure has been made in consideration
of the problem described above, and a purpose thereof is to various
embodiments described herein provide a seat with a detector capable
of appropriately restraining a warping of a connecting portion in a
transmission path for a signal that is output from a detector, when
the connecting portion is disposed inside a through hole provided
in a pad member.
[0006] According to an embodiment, a seat with a detector includes:
a detector which detects a target value that changes when a seat
occupant is seated on a seat; a first transmission path forming
portion that forms a portion extended from the detector, in the
transmission path for a signal which is output when the detector
has detected the target value; a second transmission path forming
portion that forms a portion extended from the signal receiving
unit which receives the signal, in the transmission path; a warp
restraining member which restrains a warping of a connecting
portion of a portion formed with the first transmission path
forming portion and a portion formed with the second transmission
path forming portion in the transmission path; and a through hole
formed in a pad member provided in the seat over from one end to
the other end of the pad member in a thickness direction of the pad
member; and by inserting the warp restraining member into the
through hole to pass the transmission path through inside the
through hole.
[0007] The seat with a detector configured as above restrains a
warping of a connecting portion of a portion extended from a
detector and a portion extended from a signal receiving unit in the
transmission path, with a warp restraining member. The warp
restraining member is inserted in a through hole provided in a pad
member. In this manner, the connecting portion is disposed inside
the through hole, in a state restrained from warping by the warp
restraining member.
[0008] In the seat with a detector, it is desirable that the
connecting portion comprise a fastening member that fasten the end
portions of both of the first transmission path forming portion and
the second transmission path forming portion, and the warp
restraining member restrain a warping of the connecting portion by
fixing the fastening member and the both end portions on the outer
surface of the warp restraining member. In an embodiment of the
above-described structure, a warping of the connecting portion is
restrained by fixing the fastening member and the end portion of
each of the transmission path forming portions on the outer surface
of the warp restraining member. Such a structure makes it possible
to restrain a warping of the connecting portion with a simpler
structure.
[0009] In the seat with a detector described above, it is desirable
that the warp restraining member be configured with a resin
material, and have an outer surface elliptically curved. In an
embodiment of the structure described above, the warp restraining
member is formed with a resin molding which has an outer surface
elliptically curved. In such a structure, when the fastening member
and the end portion of each of the transmission path forming
portions are fixed, it is possible to inhibit occurrence of damage,
when the outer surface of the warp restraining member abuts the
fastening member or the end portion of each of the transmission
path forming portions, since the outer surface of the warp
restraining member has no angular portion.
[0010] In the seat with a detector described above, it is desirable
that: the detectors be provided in plural numbers; the first
transmission path forming portion, the second transmission path
forming portion, and the fastening member be provided to each of
the detectors; a holder film be further provided, to be attached to
each of the first transmission path forming portion, the second
transmission path forming portion, and the fastening member of each
of the detectors, and holding each of the same; and the warp
restraining member restrains a warping of the connecting portion in
such a manner that a portion of the holder film which is attached
to the fastening member and the both end portions is fixed onto the
outer surface of the warp restraining member, in a state wound
around the warp restraining member along the outer surface. In an
embodiment of the above-described structure, the fastening member
and end portion of each of the transmission path forming portions
are fixed onto the outer surface of the warp restraining member, in
such a manner that a portion of the holder film, to which the
fastening member and the end portion of each of the transmission
path forming portions are attached is wound around the warp
restraining member. By such a structure, it becomes easy to fix the
fastening member and the end portion of each of the transmission
path forming portions onto the outer surface of the warp
restraining member.
[0011] In the seat with a detector described above, it is desirable
that: the holder film comprise a first film portion and a second
film portion adjacent to each other having different widths, the
first film portion with a larger width being a portion attached to
the fastening member and the both of end portions, wound around the
warp restraining member along the outer surface, and the second
film portion with a narrower width being attached to the first
transmission path forming portion of each of the detectors; the
warp restraining member comprise, in an end portion thereof, a
flange portion having a part notched; and the second film portion
come inside a recess portion which is formed by notching a part of
the flange portion, when the first film portion is in a state wound
around the warp restraining member. In an embodiment of the
structure described above, in the holder film, when the first film
portion with a larger width is wound around the warp restraining
member, the second film portion with a narrower width comes into
the recess portion of the flange portion. In such a structure, it
becomes possible to inhibit a positional deviation of the first
film portion, since the second film portion comes into the recess
portion to be locked on the inner wall of the recess portion, when
the first film portion is wound around the warp restraining member.
As a result, it becomes possible to favorably wind the first film
portion around the warp restraining member.
[0012] In the seat with a detector described above, it is also
desirable that the warp restraining member be inserted into the
through hole along a partial region of the inner wall of the
through hole, and the partial region of the inner wall of the
through hole form a gradient face. In an embodiment of the
structure described above, the region in the inner wall of the
through hole, along which the warp restraining member abut, forms a
gradient face. This facilitates accommodating the warp restraining
member in the through hole, and allows inhibiting a poor
functioning which may occur when the warp restraining member
protrudes from the through hole, such as a feeling of foreign
object given at seating on the seat.
[0013] In the seat with a detector described above, it is also
desirable that the partial region of the inner wall face of the
through hole form a gradient face declined such that out of the
both ends of the partial region in the thickness direction, an end
nearer to the detector is positioned forward relative to the end
farther away from the detector. In an embodiment of the structure
described above, in the partial region of the inner wall face of
the through hole forming a gradient face, the end nearer to the
detector of the partial region is positioned forward relative to
the end farther away from the detector. By such a structure, the
warp restraining member, the fastening member and the end portion
of each of the transmission path forming portions inserted into the
through hole are kept farther away from the rear end portion of the
buttocks of a seat occupant, when the seat occupant is seated on
the seat. As a result, it becomes possible to inhibit giving a seat
occupant a feeling of foreign object when seated on a seat, more
effectively.
[0014] In the seat with a detector described above, it is desirable
that: the connecting portion comprise the fastening member to which
the end portions of the first transmission path forming portion and
the second transmission path forming portion are fastened; the
detector be provided in plural numbers to positions different from
each other; the plural number of detectors comprise a first
detector and a second detector which are arranged to be spaced from
each other in a seat width direction of the seat; the first
transmission path forming portion, the second transmission path
forming portion, and the fastening member be provided to each of
the detectors; a holder film be further provided, to be attached to
each of the first transmission path forming portion, the second
transmission path forming portion, and the fastening member of each
of the detectors, and holding each of the same; a portion of the
holder film, sandwiched between the first detector and the second
detector in the seat width direction have a first extending portion
in the outer side in the seat width direction which extends along
the seat width direction, and a second extending portion in the
inner side in the seat width direction which extends along the seat
width direction at a rear position relative to the first extending
portion; and the through hole be formed to be positioned forward
relative to the second extending portion in the pad member. In an
embodiment of the above structure, the portion of the holder film,
sandwiched between the first detector and the second detector in
the seat width direction has a first extending portion in the outer
side in the seat width direction, and a second extending portion in
the inner side in the seat width direction in a rear position
relative to the first extending portion. In other words, the second
extending portion, positioned in the inner side in the seat width
direction in the portion of the holder film sandwiched between the
first detector and the second detector, is offset rearward of the
first extending portion positioned in the outer side in the seat
width direction. Then, in a space secured by offsetting the second
extending portion rearward, a through hole is formed. In other
words, it is possible to appropriately secure a space for forming a
through hole, by offsetting the second extending portion.
[0015] In the seat with a detector described above, it is also
desirable that the through hole is formed such that the rear end of
the through hole is positioned rearward of the fore-end of the
first extending portion, in a seat front to back direction. In an
embodiment of the structure described above, the through hole is
formed such that the rear end of the through hole is positioned
rearward relative to the fore-end of the first extending portion in
the seat front to back direction. By such a structure, it becomes
possible to more effectively utilize the space secured by
offsetting the second extending portion rearward.
[0016] According to an embodiment of the present disclosure, it
becomes possible that the connecting portion of the portion
extended from the detector and the portion extended from the signal
receiving unit in the transmission path for a signal output from
the detector is disposed inside the through hole provided in the
pad member, and that a warping of the connecting portion is
restrained by the warp restraining member. According to an
embodiment of the present disclosure, it also becomes possible to
restrain a warping of the connecting portion with a simpler
structure. According to an embodiment of the present disclosure, it
also becomes possible to inhibit occurrence of damage in the
fastening member or end portion of each of the transmission path
forming portions, when the fastening member and the end portion of
each of the transmission path forming portions are fixed onto the
outer surface of the warp restraining member. According to an
embodiment of the present disclosure, it becomes easy to fix the
fastening member and end portion of each of the transmission path
forming portions onto the outer surface of the warp restraining
member. According to an embodiment of the present disclosure, it
also becomes possible to favorably wind the first portion around
the warp restraining member, with inhibiting positional deviation
of the first portion. According to an embodiment of the present
disclosure, it also becomes easy to accommodate the warp
restraining member in the through hole, and it becomes possible to
inhibit a poor functioning which may occur when the warp
restraining member protrudes from the through hole, such as a
feeling of foreign object given at the time of seating on the seat.
According to an embodiment of the present disclosure, it also
becomes possible to more effectively inhibit giving a seat occupant
a feeling of foreign object, at the time of seating on the seat.
According to an embodiment of the present disclosure, it also
becomes possible to appropriately secure a space for forming a
through hole, by offsetting the second extending portion positioned
in the inner side in the width direction rearward, in the portion
of the holder film sandwiched between the first detector and the
second detector. According to an embodiment of the present
disclosure, it also becomes possible to more effectively utilize
the space secured by offsetting the second extending portion
rearward.
BRIEF DESCRIPTION OF DRAWINGS
[0017] Various embodiments of the invention are illustrated in the
drawings in which:
[0018] FIG. 1 is a view showing an overall perspective of a seat
with a detector according to a first embodiment;
[0019] FIG. 2 is a conceptual view showing a transmission path for
an output-signal from a detector, according to an embodiment;
[0020] FIG. 3 is a view showing a manner of attaching a detector to
a pad member, according to an embodiment;
[0021] FIG. 4 is a plan view showing detectors, transmission path
forming portions, fastening members, and a holder film, according
to an embodiment;
[0022] FIG. 5 is a plan view showing locations of detectors,
according to an embodiment;
[0023] FIG. 6 is a perspective view showing a warp restraining
member, according to an embodiment;
[0024] FIG. 7 is a view showing a sensor unit before wound around a
warp restraining member, according to an embodiment;
[0025] FIG. 8 is a view showing a sensor unit after wound around a
warp restraining member, according to an embodiment;
[0026] FIG. 9 is a view of the sensor unit shown in FIG. 8, when
viewed from the A-A direction in the figure, according to an
embodiment;
[0027] FIG. 10 is a view of the pad member and the sensor unit
shown in FIG. 5, when cut through the B-B cross section in the
figure, according to an embodiment;
[0028] FIG. 11 is a view showing a seat with a detector, according
to a modified example;
[0029] FIG. 12 is a perspective view showing an overall structure
of a vehicle seat according to a second embodiment;
[0030] FIG. 13A is a schematic front view showing a seat back
comprising upper electrode units constituting heartbeat sensors,
according to an embodiment;
[0031] FIG. 13B is a schematic plan view showing a seat cushion
comprising rear-electrode units and fore-electrode units
constituting heartbeat sensors, and a respiration sensor, according
to an embodiment;
[0032] FIG. 14 is an enlarged view showing an upper electrode unit,
according to an embodiment;
[0033] FIG. 15 is a cross-sectional view of a part of the upper
electrode unit, which is a view showing the XV-XV cross section of
FIG. 14, according to an embodiment;
[0034] FIG. 16 is an enlarged view showing a rear-electrode unit,
according to an embodiment;
[0035] FIG. 17 is an enlarged view showing a fore-electrode unit,
according to an embodiment;
[0036] FIG. 18 is a schematic plan view showing a seat cushion
comprising rear-electrode units and fore-electrode units
constituting heartbeat sensors, and a respiration sensor, according
to another embodiment;
[0037] FIG. 19 is a perspective view showing an overall structure
of a vehicle seat according to a third embodiment;
[0038] FIG. 20 is a schematic front view showing a seat back,
according to an embodiment; and
[0039] FIG. 21 is a side cross-sectional view of the seat back,
which is a view showing the XXI-XXI cross section of FIG. 20,
according to an embodiment.
DETAILED DESCRIPTION
Seat with Detector According to First Embodiment of Present
Disclosure
[0040] In the description below, a seat with a detector according
to a first embodiment of the present disclosure (the present
embodiment) is explained. Hereinbelow, an explanation is given with
a vehicle seat mounted in a vehicle described as an example seat.
In the following explanation, "front to back direction" corresponds
to the front to back direction of the seat, which refers to the
front to back direction when viewed from a seat occupant seated on
a vehicle seat, specifically, the front to back direction (in other
words, the traveling direction) of the vehicle. "Width direction"
corresponds to the width direction of the seat, which refers to the
right to left direction when viewed from a seat occupant seated on
a vehicle seat. The embodiments explained below are an example for
facilitating understanding of the present disclosure, and do not
limit the present disclosure. In other words, a shape, a dimension,
an arrangement, or the like of a member explained below may be
changed or improved without deviating from the gist of the present
disclosure, and the present disclosure naturally comprise
equivalents thereof.
[0041] In general, a basic structure of the vehicle seat according
to the present embodiment (hereinbelow, present seat S) is the same
as a structure of an ordinary vehicle seat. In other words, as
shown in FIG. 1, the present seat S comprises a seat cushion S1
which supports buttocks of a seat occupant from below, a seat back
S2 which supports back of a seat occupant from behind, and a
headrest S3 which supports head of a seat occupant. FIG. 1 is a
view showing an overall perspective of the present seat S.
[0042] The seat cushion S1 and the seat back S2 are configured by
setting a pad member comprising urethane or the like in a seat
frame which is not illustrated, and then covering the pad member
with a covering material. In this connection, in the pad member of
each of the seat cushion S1 and the seat back S2, a groove for
hanging the covering material (hanging groove) is formed long along
a predetermined direction.
[0043] The present seat S also comprises a pressure sensor 1 as a
detector. More particularly, the present seat S comprises multiple
(e.g., a plural number of) pressure sensors 1, and the plural
number of pressure sensors 1 are provided directly below the
seating face of the seat cushion 1, in a unitized state. Each of
the pressure sensors 1 detects, at individual location, a pressure
(a seating pressure) applied to a seating face when a seat occupant
is seated on the present seat S. Here, the seating pressure refers
to a value which periodically changes according to biological
activity, specifically, respiration of a seat occupant, which is a
target value to be detected by the pressure sensor 1.
[0044] The pressure sensor 1 comprises a publicly known pressure
sensor, for example, a piezoelectric sensor-type pressure sensor, a
semiconductor-piezoresistive-type pressure sensor, a strain
gauge-type pressure sensor, a capacitance-type pressure sensor, or
a silicon resonant-type pressure sensor, or the like.
[0045] In the present embodiment, the unit comprising the plural
number of pressure sensors 1 (hereinbelow, sensor unit 10) is
provided in a rear side portion of the seat cushion S1, as shown in
FIG. 1 with a broken line. Each of the pressure sensors 1 in the
sensor unit 10 is disposed in a position sandwiched between the pad
member constituting the seat cushion 1 and the covering material
covering the pad member, to detect a seating pressure in a high
accuracy. However, there is no limitation in sensor location, so
long as it is a position where it is possible to detect a seating
pressure with suitable accuracy. For example, the pressure sensor 1
may be disposed above the seating face of the seat cushion S1.
[0046] Upon detecting a seating pressure, the pressure sensor 1
outputs a signal according to the detected result. Such an
output-signal is received by an ECU (Electronic Control Unit) 2, as
shown in FIG. 2. In other words, in the present embodiment, an ECU
2 functions as a signal receiving unit which receives an
output-signal from each of the pressure sensors 1. FIG. 2 is a
conceptual view showing the transmission paths for output-signals
from the pressure sensors 1.
[0047] Further, the ECU 2 according to the present embodiment is
configured to function as a signal processing unit, subjecting a
received signal to a signal processing such as a noise removal
process, an A/D conversion process, etc. Furthermore, the ECU 2
according to the present embodiment is configured to function as a
numerical processing unit, carrying out a numerical processing to
determine a biological condition of a seat occupant, on the basis
of the processed signal. The "biological condition of a seat
occupant" refers to a condition relating to normality/abnormality
of an action or a function of each body portion (including an
internal organ or a nerve) of a seat occupant, such as wakefulness
or alertness condition, mental tranquility condition, heavy
inebriation condition, etc. In an embodiment, the ECU 2 according
to the present embodiment has a function of determining wakefulness
condition of a seat occupant.
[0048] In an embodiment, a hardware configuration of the ECU 2
includes an input port and a controller. The controller receives an
output-signal from the pressure sensor 1 which has been input to
the input port to a suitable signal processing unit, and by using
the signal after being processed (e.g., digital signal processing),
carries out a numerical processing. As a result of such a numerical
processing, a wakefulness condition of a seat occupant at the point
of time is determined. In this connection, as a method for
determining a wakefulness condition of a seat occupant on the basis
of a detected result (namely, a detected value of a seating
pressure), publicly known determination methods are available. For
example, it is possible to determine a wakefulness condition of a
seat occupant, by distinguishing a wave form which shows a periodic
change of a seating pressure from a detected result from the
pressure sensor 1, and determining a wakefulness condition of a
seat occupant on the basis of a length of a cycle (plainly, space
between peaks) of the wave.
[0049] The ECU 2 according to the present embodiment is disposed in
a lower position of the seat cushion S1. In other words, in the
present embodiment, the ECU 2 is provided to be disposed in the
side opposite to the pressure sensor 1 across the pad member P of
the seat cushion S1. In addition, the ECU 2 according to the
present embodiment is disposed rearward of any of the plural
pressure sensors 1.
[0050] As described above, in the present embodiment, the ECU 2
which receives output-signals from the pressure sensor 1 is
disposed in the side opposite to the pressure sensor 1, across the
pad member P. In the present embodiment, a through hole 20 is
formed in the pad member 20 as shown in FIG. 3, so that a
transmission path for output-signals from the pressure sensor 1 is
laid to the ECU 2 in such a structure. Inside this through hole 20,
a portion of the sensor unit 10, which forms the transmission paths
for signals (the transmission path forming portion) is passed
through, so that the transmission paths pass inside the through
hole 20, and ends of the transmission paths are connected to the
ECU 2. FIG. 3 is a view showing a manner of attaching the sensor
unit 10 to the pad member P of the seat cushion S1.
[0051] Hereinbelow, the sensor unit 10 and a structure configured
to attach the sensor unit 10 to the pad member P are explained in
detail. The sensor unit 10 is mainly comprised of the pressure
sensors 1, the leading wires 3 as the first transmission path
forming portions, the cables 4 as the second transmission path
forming portions, terminal linking members 5 as the fastening
members, and the holder film 6, as shown in FIG. 4. FIG. 4 is a
plan view showing the sensor unit 10 in a developed state.
[0052] The pressure sensor 1 is provided to the sensor unit 10 in
plural numbers, as set forth above. In the present embodiment, six
pieces are provided as shown in FIG. 4. However, the number of the
pressure sensor 1 is not limited to six, but may be set to
arbitrary number of two or more. In the explanation below, each of
the six pressure sensors 1 is referred to as pressure sensor A,
pressure sensor B, pressure sensor C, pressure sensor D, pressure
sensor E, and pressure sensor F, when distinguished from each
other.
[0053] In a state that the sensor unit 10 is attached to the pad
member P, the six pressure sensors 1 are disposed such that
locations of each of the pressure sensors 1 have coordinates
different from each other in the XY coordinate space, as shown in
FIG. 5. Here, the XY coordinate space refers to a two-dimensional
coordinate space defined when two of the width direction and the
front to back direction are set as axial directions of the
coordinate axes. In this connection, coordinates of the origin
position in the XY coordinate space is explained such that the X
coordinate is the center position of the seating face in the width
direction, and the Y coordinate is a position somewhat rear to the
center position in the front to back direction of the seating face.
FIG. 5 is a plan view showing locations of each of the pressure
sensors 1. In FIG. 5, some of the parts other than the pressure
sensors 1 (for example, the leading wires 3) are omitted for easy
understanding of the locations of the pressure sensors 1.
[0054] As for locations of the pressure sensors 1, it is explained
more particularly such that the six pressure sensors 1 are disposed
separately in front and back as shown in FIG. 5. Specifically, four
pressure sensors 1 in the rear-side, and two pressure sensors 1 in
the fore-side are each disposed in a line along the width
direction. The six pressure sensors 1 are disposed bilaterally
symmetrically across the Y-axis (namely, the center position in the
width direction of the seating face). In an embodiment, coordinates
of locations of each of the pressure sensors 1 are as follows:
(Location of pressure sensor A)=(Xa, 0), wherein Xa is any real
number larger than 0, (Location of pressure sensor B)=(Xb, 0),
wherein Xb is a real number larger than 0 and smaller than Xa,
(Location of pressure sensor C)=(Xb, Yc), wherein Yc is any real
number larger than 0, (Location of pressure sensor D)=(-Xb, Yc),
(Location of pressure sensor E)=(-Xb, 0), (Location of pressure
sensor F)=(-Xa, 0),
[0055] In the transmission path for a signal output from the
pressure sensors 1, the leading wire 3 forms a portion extended
from the pressure sensor 1, and comprises a metal wire having a
relatively small wire diameter, and an insulating coating. This
leading wire 3 is provided to each of the pressure sensors 1. In
other words, the sensor unit 10 has six leading wires 3 in
total.
[0056] In the transmission path for a signal output from the
pressure sensors 1, the cable 4 forms a portion extended from the
ECU 2, and comprises a wire material having a wire diameter
somewhat larger than that of the leading wire 3. This cable 4 is
also provided to each of pressure sensors 1 similarly as the
leading wire 3. In other words, the sensor unit 10 has six cables 4
in total. The six cables 4 are bundled at a position before
connected to the ECU 2, and then connected to the ECU 2 as a plied
wire.
[0057] In the transmission path for a signal output from the
pressure sensor 1, the terminal linking member 5 forms a connecting
portion of the portion formed with the leading wire 3 and the
portion formed with the cable 4. More specifically, the terminal
linking member 5 comprises a metal fragment with a suitable
conductivity, and to one end thereof, an end portion of the leading
wire 3 is fastened, and to the other end thereof, an end portion of
the cable 4 is fastened. The terminal linking member 5 is provided
to each of the pressure sensors 1. In other words, the sensor unit
10 has six terminal linking members 5 in total.
[0058] The holder film 6 has a front layer and a back layer, and
sandwiches and holds between these two layers, six pressure sensors
1, and a leading wire 3, a cable 4, and a terminal linking member 5
for each of the pressure sensors 1. In other words, in the sensor
unit 10, each of the pressure sensors 1, and a leading wire 3, a
cable 4, and a terminal linking member 5 for each of the pressure
sensor 1 are held in the holder film 6 by being attached to the
holder film 6. The holder film 6 comprises a material having a
suitable conductivity, for example, polyethylene naphthalate. The
holder film 6 also has a thickness and a flexibility of an extent
which allows the film to be easily deformed.
[0059] The holder film 6 according to the present embodiment is
roughly divided into three regions as shown in FIG. 4, which
specifically are a sensor attachment unit 6A, an intermediate
portion 6B, and an expanded portion 6C. In the holder film 6, the
sensor attachment unit 6A is a region where the pressure sensor 1
is attached. In a state that the sensor unit 10 is attached to the
pad member P, the sensor attachment unit 6A is placed on the upper
face of the pad member P, that is, on a face in the side to which a
load is applied from an occupant.
[0060] To the sensor attachment unit 6A, the leading wires 3
extended from the pressure sensors 1 are also attached, in addition
to the pressure sensors 1. The leading wires 3 extended from each
of the pressure sensors 1 extend along the periphery of the sensor
attachment unit 6A, toward the intermediate portion 6B, as shown in
FIG. 4.
[0061] The sensor attachment unit 6A is explained more particularly
such that the sensor attachment unit 6A comprises substantially
circular portions to which the pressure sensors 1 are attached, and
substantially linearly extended portions through which two pressure
sensors 1 communicate with each other, as shown in FIG. 4. Among
them, the portions through which the pressure sensors 1 communicate
with each other are provided individually between the pressure
sensors A and B, between the pressure sensors B and C, between the
pressure sensors C and D, between the pressure sensors D and E, and
between the pressure sensors E and F. The portion through which the
pressure sensors C and D communicate with each other extends in the
width direction, as shown in FIG. 5, in a state that the sensor
unit 10 is attached to the pad member P. Here, the pressure sensors
C and D are disposed the most forward among the six pressure
sensors 1, and are two pressure sensors 1 (which correspond to the
first detector and the second detector) arranged to be spaced in
the width direction. In this sense, it can be said that the portion
in the sensor attachment unit 6A, through which the pressure
sensors C and D communicate with each other corresponds to the
portion sandwiched between the first detector and the second
detector in the width direction.
[0062] In addition, the portion through which the pressure sensors
C and D communicate with each other comprises a first extending
portion 6m located in the outer side in the width direction, and a
second extending portion 6n located in the inner side in the width
direction, as shown in FIG. 5. Two first extending portions 6m are
provided to sandwich the second extending portion 6n, each
extending linearly along the width direction. The second extending
portion 6n extends linearly along the width direction at a
rear-position relative to the first extending portion 6m. In other
words, in the sensor attachment unit 6A of the holder film 6, the
portion through which the pressure sensors C and D communicate with
each other is in a configuration that the center portion in the
width direction (the portion corresponding to the second extending
portion 6n) is somewhat offset rearward.
[0063] The intermediate portion 6B is a substantially belt-shaped
portion extended from the second extending portion 6n, and middle
positions of the leading wires 3 extended from the pressure sensors
1 are attached thereto. More particularly, as shown in FIG. 4, six
leading wires 3 in total are attached to the intermediate portion
6B to be arranged at equal intervals and in parallel. In a state
that the sensor unit 10 is attached to the pad member P, the
intermediate portion 6B enters the through hole 20 of the pad
member P from its middle position.
[0064] The expanded portion 6C is a portion (a portion
corresponding to the first portion) adjacent to the intermediate
portion 6B on the side opposite to the sensor attachment unit 6A,
which is wider than the intermediate portion 6B and has
substantially rectangular shape. In other words, the intermediate
portion 6B is a portion (a portion corresponding to the second
portion) adjacent to the expanded portion 6C, which is narrower
than the expanded portion 6C. Attached to the expanded portion 6C
are: the leading wires 3 extended from the pressure sensors 1, the
cables 4 extended from the ECU 2, and the terminal linking members
5 which fasten the end portions of the leading wires 3 and the end
portions of the cables 4. More specifically, in the expanded
portion 6C, the leading wires 3 individually provided to the
pressure sensors 1, cables 4 and the terminal linking member 5
(hereinbelow, the leading wires 3 etc.) are arranged at equal
intervals and in parallel, as shown in FIG. 4.
[0065] The interval at which the leading wires 3 etc. are arranged
in the expanded portion 6C is wider than the interval at which the
leading wires 3 are arranged in the intermediate portion 6B. This
is to prevent adjacent terminal linking members 5 from contacting
each other in the expanded portion 6C. Further, as shown in FIG. 4,
the six terminal linking members 5 are disposed such that positions
thereof are aligned in an end portion in the extending direction of
the expanded portion 6C (the end portion in the side opposite to
the side where the intermediate portion 6B is positioned). However,
location of the terminal linking members 5 is not limited to the
above, but may be shifted from each other in the extending
direction of the expanded portion 6C.
[0066] In a state that the sensor unit 10 is attached to the pad
member P, substantially all of the expanded portion 6C is
accommodated in the through hole 20 of the pad member P. On the
other hand, in the cable 4, a portion in the side more proximal
than the expanded portion 6C, comes out from the lower end of the
through hole 20, and extends to the ECU 2.
[0067] As above, in the present embodiment, since the expanded
portion 6C is accommodated in the through hole 20 in the state that
the sensor unit 10 is attached to the pad member P, the terminal
linking member 5 is supposed to also be accommodated in the through
hole 20. In other words, in the transmission paths for
output-signals from the pressure sensors 1, the connecting portions
of the portion formed with the leading wires 3 and the portion
formed with the cables 4 are provided to be positioned inside the
through hole 20. In addition, being positioned inside the through
hole 20 makes the connecting portion disposed in an appropriate
position relative to the pad member P.
[0068] Specifically, if the terminal linking members 5 constituting
the connecting portions are on the upper face of the pad member P,
there is a concern that a seat occupant has a feeling of a foreign
object when seated on the present seat S. On the other hand, if the
terminal linking members 5 are in a lower position of the pad
member P, there is a concern that the seat frame that support the
pad member P from below and the terminal linking member 5 interfere
with each other. In addition, the holder film 6, to which the
terminal linking member 5 is attached, should be extended also to
the lower position of the pad member P, which may similarly result
in the concern of interfering with the seat frame to damage itself.
On the other hand, if the terminal linking members 5 and the
expanded portion 6C of the holder film 6 to which the terminal
linking members 5 are attached are accommodated in the through hole
20 formed in the pad member P, the inconvenience described above is
inhibited, and it becomes possible to appropriately protect the
terminal linking members 5 and the holder film 6.
[0069] However, when a relatively large load is applied around the
through hole 20, there is a possibility that the load is
transmitted to the terminal linking members 5, even if the terminal
linking members 5 constituting the connecting portions are disposed
in the through hole 20. In such a case, there is a concern that the
terminal linking members 5 (namely, the connecting portions of the
signal transmission paths) are warped and damaged. In particular,
when a seat occupant kneels up on the seat cushion S1, a
significantly increased load is applied to the portion of the pad
member P where the seat occupant put his knee. At this time, if a
knee of the seat occupant is put around the through hole 20, there
is a concern that an excessive load is applied to the terminal
linking members 5 in the through hole 20, and in this case, the
terminal linking members 5 is warped and damaged together with the
holder film 6.
[0070] Thus, in order to restrain a warping of the connecting
portion as described above, the present embodiment uses a warp
restraining member 12, and disposes the warp restraining member 12
together with the terminal linking members 5, inside the through
hole 20. Hereinbelow, the warp restraining member 12 is
specifically explained.
[0071] The warp restraining member 12 is a part formed with a resin
material such as plastic or silicone rubber, and has a suitable
hardness to restrain a warping of the connecting portion. The warp
restraining member 12 also has an outline shape as illustrated in
FIG. 6. FIG. 6 is a perspective view showing the warp restraining
member 12.
[0072] In the present embodiment, the warp restraining member 12
comprises a cylindrical body having an elliptical cross section,
and has an elliptically curved outer surface 12a. The warp
restraining member 12 is not limited to a hollow body such as a
cylindrical body, but may also be a solid body. The cross-sectional
shape of the warp restraining member 12 is not limited to an
elliptical shape, but may also be a circular shape or a polygonal
shape.
[0073] The warp restraining member 12 comprises a flange portion
12b projected out from an end portion of the outer surface 12a.
This flange portion 12b is formed over the entire circumference of
the warp restraining member 12. As shown in FIG. 6, the flange
portion 12b has a part rectangularly notched, which forms a recess
portion 12c. The width of the recess portion 12c (the length in the
circumferential direction of the warp restraining member 12) is
slightly longer than the width of the intermediate portion 6B of
the holder film 6.
[0074] The warp restraining member 12 configured as above restrains
a warping of the connecting portion by fixing the terminal linking
members 5 and each end portion of the leading wires 3 and the
cables 4 fastened to the terminal linking members 5 onto the outer
surface 12a thereof. Specifically, a portion of the holder film 6,
to which the terminal linking members 5 and the each end portion of
the leading wires 3 and the cables 4 are attached, namely, the
expanded portion 6C, is wound around the warp restraining member 12
along the outer surface 12a. In this manner, the terminal linking
members 5 and the each end portion of the leading wires 3 and the
cables 4 are fixed onto the outer surface 12a of the warp
restraining member 12.
[0075] More particularly, in the expanded portion 6C, in the region
in which the terminal linking members 5 are arranged, every
terminal linking member 5 is individually covered with an
insulating tape 7, as shown in FIG. 7. This allows avoiding contact
of the terminal linking members 5 to each other, when the expanded
portion 6C is wound around the warp restraining member 12. FIG. 7
is a view showing the sensor unit 10 in a step before the expanded
portion 6C is wound around the warp restraining member 12.
[0076] The expanded portion 6C, in a state that the region having
the terminal linking members 5 arranged is covered with the
insulating tape 7, is wound around the warp restraining member 12,
and then, the expanded portion 6C wound around the warp restraining
member 12 is fixed thereto by being wrapped with an adhesive tape
T. In this manner, the portions of the sensor unit 10
(specifically, the leading wires 3, the cables 4, and the terminal
linking members 5) attached to the expanded portion 6C of the
holder film 6 surround the warp restraining member 12 as a core
material, as shown in FIG. 8. FIG. 8 is a view showing the sensor
unit 10 in a state that the expanded portion 6C is wound around the
warp restraining member 12.
[0077] In this connection, when the expanded portion 6C is wound
around the warp restraining member 12, the intermediate portion 6B
of the holder film 6 comes into the recess portion 12c formed in
the flange portion 12b of the warp restraining member 12, as shown
in FIG. 9. FIG. 9 is a view of the sensor unit 10 illustrated in
FIG. 8, when viewed from the A-A direction of the figure.
[0078] Accordingly, even when a positional deviation of the
expanded portion 6C is concerned at the time the expanded portion
6C is wound around the warp restraining member 12, such positional
deviation is generally inhibited, since the intermediate portion 6B
comes into the recess portion 12c to lock a side edge of the
intermediate portion 6B on the inner wall of the recess portion
12c. As a result, it becomes possible to favorably wind the
expanded portion 6C around the warp restraining member 12. In an
embodiment, the structure configured to inhibit the positional
deviation of the expanded portion 6C at the time the expanded
portion 6C is wound around the warp restraining member 12 is not
limited to the recess portion 12c formed in the flange portion 12b.
For example, it is possible to provide a projection for positional
deviation inhibition on the outer surface 12a of the warp
restraining member 12.
[0079] Moreover, by providing the recess portion 12c in the flange
portion 12b, it becomes unnecessary to pass the intermediate
portion 6B and the leading wires 3 attached to the intermediate
portion 6B over the flange portion 12b. This allows for inhibiting
the leading wires 3 from being damaged by abutting the edge of the
flange portion 12b, or by other things.
[0080] Further, in the present embodiment, the outer surface 12a of
the warp restraining member 12 is elliptically curved. In other
words, since the outer surface 12a has no angular portion, it
becomes possible to inhibit occurrence of damage when the expanded
portion 6C abuts the outer surface 12a, at the time the expanded
portion 6C is wound around the warp restraining member 12. However,
shape of the outer surface 12a of the warp restraining member 12 is
not particularly limited, and the outer surface 12a may be warped
into a polygonal shape, having angular portions.
[0081] As above, the terminal linking members 5, together with the
leading wires 3, the cables 4, and the expanded portion 6C are
reinforced by the warp restraining member 12, by being fixed to the
outer surface 12a of the warp restraining member 12. In other
words, it becomes possible to inhibit a warping of the terminal
linking members 5, even if a load is input to the terminal linking
members 5, by resisting the input load, since the terminal linking
members 5 become supported by the warp restraining member 12 having
a sufficient hardness.
[0082] Then, the warp restraining member 12, around which the
expanded portion 6C is wound, is inserted into the through hole 20,
when the sensor unit 10 is attached to the pad member P. In this
manner, the transmission paths for output-signals from each of the
pressure sensors 1 are passed through the through hole 20. Then, a
warping of the terminal linking members 5 (namely, a warping of the
connecting portions) is generally restrained by the warp
restraining member 12, inside the through hole 20.
[0083] In the present embodiment, in a state that the sensor unit
10 is attached to the pad member P, the warp restraining member 12
is fully accommodated in the through hole 20 (that is to say, not
protruded out from the through hole 20). In this manner, a seat
occupant is inhibited from having a feeling of foreign object, when
seated on the present seat S. Hereinbelow, a positional
relationship of the warp restraining member 12 and the through hole
20 is explained.
[0084] To explain a positional relationship of the warp restraining
member 12 and the through hole 20, firstly, the through hole 20 and
surrounding configuration are explained with reference to FIG. 5.
In the pad member P, the through hole 20 is formed over from one
end (the upper end) to the other end (the lower end) in the
thickness direction of the pad member P. An opening in the upper
end side of the through hole 20 is made slightly larger than the
periphery of the warp restraining member 12 (strictly, the
periphery of the flange portion 12b).
[0085] In the present embodiment, the through hole 20 is formed in
a position forward of the six pressure sensors 1 and the sensor
attachment unit 6A of the holder film 6, as shown in FIG. 5. This
is because, since the pressure sensors 1 are disposed rearward in
the seat cushion S1, if the through hole 20 is formed further
rearward thereof, a seat occupant will have an unusual feeling when
seated on the present seat S. The through-hole 20 is formed in the
center portion of the pad member P in the width direction, as shown
in FIG. 5. This reflects the fact that the six pressure sensors 1
and the sensor attachment unit 6A of the holder film 6 are in a
formation bilaterally symmetric across the widthwise center
position of the seat cushion S1.
[0086] Besides, in the present embodiment, a hanging groove Pa for
hanging a covering material is formed along the width direction,
each forward and rearward of the portion of the pad member P, where
the six pressure sensors 1 and the sensor attachment unit 6A of the
holder film 6 are disposed. The through hole 20 is formed in a
position slightly rearward of the hanging groove Pa in the
fore-side, as shown in FIG. 5. This is because, if the through hole
20 is formed in a position forward relative to the fore-side
hanging groove Pa, a part of the leading wire 3 or the holder film
6 should be arranged in a manner straddling across the hanging
groove Pa, which may cause a trouble during the work of hanging the
covering material.
[0087] On the other hand, in the sensor attachment unit 6A of the
holder film 6, the portion through which the pressure sensors C and
D communicate with each other has the center portion in the width
direction (the portion corresponding to the second extending
portion 6n) offset rearward, as set forth above. In other words, a
space is provided forward of the widthwise center portion of the
portion through which the pressure sensors C and D communicate with
each other. Then, the present embodiment utilizes the secured space
for forming a through hole 20, as shown in FIG. 5. In other words,
in the present embodiment, a space for forming the through hole 20
is appropriately secured, by rearwardly offsetting a part of the
portion through which the pressure sensors C and D communicate with
each other in the sensor attachment unit 6A.
[0088] Further, in the present embodiment, the through hole 20 is
formed such that the rear end of the through hole 20 is positioned
rearward relative to the fore-end of the widthwise end portion of
the portion through which the pressure sensors C and D communicate
with each other (the portion corresponding to the first extending
portion 6m), as shown in FIG. 5. In this manner, it becomes
possible to more effectively utilize the space secured by
rearwardly offsetting the widthwise center portion of the portion
through which the pressure sensors C and D communicate with each
other, as a space for forming the through hole 20.
[0089] Next, a positional relationship of the warp restraining
member 12 and the through hole 20 is explained. In a state that the
sensor unit 10 is attached to the pad member P, the warp
restraining member 12 is inserted in the through hole 20, in a
state along a partial region of the inner wall face of the through
hole 20. More specifically, as shown in FIG. 10, in the inner wall
face of the through hole 20, the rear side region forms a gradient
face 20a. As shown in the figure, the gradient face 20a is inclined
such that the upper end (the end closer to the pressure sensor 1)
out of both ends in the thickness direction of the pad member P is
positioned forward relative to the lower end (the end more distant
from the pressure sensor 1). FIG. 10 is a schematic cross-sectional
view of the pad member P and the sensor unit 10 illustrated in FIG.
5, when cut at the B-B cross section in the figure.
[0090] The warp restraining member 12 is inserted in the through
hole 20, in a state along the region which forms the gradient face
20a of the inner wall face of the through hole 20. In other words,
the warp restraining member 12 is provided to be disposed in the
through hole 20, in an inclined (strictly, forwardly inclined)
state relative to the thickness direction of the pad member P. In
this manner, the warp restraining member 12 is accommodated within
the through hole 20. More specifically, when the thickness of the
pad member P is relatively thin, when the warp restraining member
12 is inserted into the through hole 20 in a state along the
thickness direction of the pad member P, a portion of the warp
restraining member 12 (e.g. the lower end portion) may sometimes
protrudes from the through hole 20. In contrast, when the warp
restraining member 12 is inserted into the through hole 20 in a
state inclined relative to the thickness direction of the pad
member P, it is possible to accommodate the entire warp restraining
member 12 within the through hole 20, even if the thickness of the
pad member P is thin.
[0091] In addition, the gradient face 20a as set forth above is
positioned more rearwardly as it is inclined from the upper end to
the lower end. Accordingly, the upper end portion (the end portion
closer to the pressure sensor 1) of the warp restraining member 12
in the state along the gradient face 20a is positioned more
forwardly and the lower end portion (the end portion more distant
from the pressure sensor 1) is positioned more rearwardly. In this
manner, it becomes possible to effectively inhibit a seat occupant
from having a feeling of foreign object due to the warp restraining
member 12, when the seat occupant is seated on the present seat
S.
[0092] More clearly, in the warp restraining member 12 in the
through hole 20, the upper end portion which is closer to the
buttocks of a seat occupant is positioned forward in the seat
cushion S1. In other words, when the seat occupant is seated on the
present seat S, the upper end portion of the warp restraining
member 12 is in a position forward of the buttocks of the seat
occupant, specifically, nearly to the crotch. Thus, it is avoided
in advance that the seat occupant has a feeling of foreign object
due to the upper end portion of the warp restraining member 12. On
the other hand, the lower end portion of the warp restraining
member 12 is positioned more rearward in the seat cushion S1.
However, since the lower end portion (strictly, the lower end
portion and the center portion) of the warp restraining member 12
is sufficiently distant from the buttocks of a seat occupant, it is
unlikely that the seat occupant has a feeling of foreign object due
to the lower end portion of the warp restraining member 12.
[0093] As is clear from the above reasons, according to such a
structure that the gradient face 20a inclines to be positioned
rearward as it inclines from the upper end to the lower end, it
becomes possible to effectively inhibit a seat occupant from being
given a feeling of foreign object, when seated on a seat.
[0094] In this connection, the gradient pattern of the gradient
face 20a is not limited to the above contents, but for example, the
gradient face may incline to be positioned forward as it inclines
from the upper end to the lower end. Alternatively, the gradient
face may incline to be positioned leftward (or rightward) as it
inclines from the upper end to the lower end. However, from the
viewpoint of inhibiting the feeling of foreign object at seating,
the gradient pattern as set forth above is desirable, that is to
say, the gradient face desirably inclines to be positioned
rearward, as it inclines from the upper end to the lower end.
Another Embodiment
[0095] In the embodiment described above, the pressure sensors 1 as
detectors were provided to be disposed in the position directly
below the seating face of the seat cushion S1. However, in terms of
kinds of detectors and locations thereof, another example may be
provided. As for the detectors, it is only requested to detect a
target value which changes when a seat occupant is seated on the
seat. For example, it is possible to use a shape sensor which
detects a value according to a bone structure of a seat occupant (a
bone structure of a portion which is in contact with the seat in
the body of the seat occupant), or an electric potential sensor
which detects a body electric potential of a seat occupant. As for
locations of the detectors, it is not limited to the upper face of
the pad member P of the seat cushion S1, but may also be a surface
other than the upper surface (e.g., the lower face) of the pad
member P. Alternatively, it may be the front face or the back face
of the pad member P of the seat back S2.
[0096] Moreover, in the embodiment described above, in order to
restrain a warping of the terminal linking members 5, the expanded
portion 6C of the holder film 6 to which the terminal linking
members 5 are attached is wound around the warp restraining member
12, such that the terminal linking members 5 are fixed onto the
outer surface 12a of the warp restraining member 12. However, a
structure configured to restrain a warping of the terminal linking
members 5 with the warp restraining member 12 is not limited to the
above contents. For example, it is possible to restrain a warping
of the terminal linking members 5, by inserting the terminal
linking members 5 and the expanded portion 6C into the hole of the
warp restraining member 12 having a cylindrical body.
[0097] Further, although the above embodiment has been explained
with taking a vehicle seat as an example of application of the
present disclosure, the application is not limited thereto. The
present disclosure is also applicable to a general administrative
chair C1 as illustrated in FIG. 11. FIG. 11 is a view showing an
administrative chair C1 provided with the sensor unit 10, as a seat
with a detector according to a modified example. The present
disclosure is also applicable to a seat for carriage other than
those used in vehicles.
Seat Capable of Measuring Biosignal According to Second Embodiment
of Present Disclosure
[0098] The seat according to the second embodiment of the present
disclosure relates to a seat capable of stably measuring biosignals
of seat occupants, even when seat occupants vary in physique, and
at the same time, capable of improving accuracy of wakefulness
determination.
[0099] In recent years, in order to promptly inform of an
occurrence of physical disorder of an occupant of a vehicle, if
occurred, structures for detecting various parameters indicating
conditions of an occupant of a vehicle to determine a physical
disorder have been proposed. For example, Japanese Patent
Publication JP 2009-106673 discloses a vehicle seat which comprises
heartbeat sensors (described as electrocardiographic sensors in the
publication) comprising heartbeat sensor electrodes (described as
electrocardiographic sensor electrodes in the publication) disposed
in a seat back, and a ground electrode disposed in a seat cushion.
The heartbeat sensors detect electric potential signals from a
heart of a seat occupant, as parameters indicating a condition of
the occupant, to monitor a health condition.
[0100] Japanese Patent Publication JP 2007-301175 discloses an
invention related to a biosignal collecting device comprising
planar electrode groups in positions abutting the back, the waist
to the buttocks, and the thighs of a seat occupant, which detects
biosignals from difference signals of electric potential signals
detected from each of the planar electrode groups. More
specifically, the electric potential signals are electric potential
signals emitted from around a heart or a lung, on the basis of
which, the biosignal collecting device collects a biosignal of
heartbeat, respiration, etc. of a seat occupant, with inhibiting
signal noise, by setting one of the plural number of planar
electrodes as one from which a neutral point electric potential for
an amplifier is obtained.
[0101] In an embodiment, during an operation of a car, a contacting
portion of a seat occupant and a seat is variable, due to
occurrence of jolting, and centrifugal force that works during
running on a curve, etc. Moreover, when physique of seat occupants
varies, a point where a biosignal is appropriately detected varies.
Therefore, it has been difficult to stably detect a biosignal from
a seat occupant. This problem has been particularly noticeable when
a biosignal detected by a sensor provided to a seat back is
targeted. The reason thereof is that in a seat back, a contacting
portion with a seat occupant which changes to front or back and to
right or left due to jolting of a car, and significantly varies
depending on difference in physique of seat occupants. By the
heartbeat sensors described in the JP 2009-106673 Publication, it
was difficult to appropriately detect an electrocardiographic
signal for the reason above, since the heartbeat sensor electrodes
were provided only in the seat back.
[0102] On the other hand, the planar electrode group described in
the JP 2007-301175 Publication is capable of obtaining an electric
potential signal more stable than the one described in the JP
2009-106673 Publication, for having arbitrary one of the planar
electrodes as a ground electrode, while obtaining electric
potential signals from the other two, and because the electric
potential signals are signals relating to heartbeat and
respiration. However, the signals detected for heartbeat and
respiration by the planar electrode group described in the JP
2007-301175 Publication are only electric potential signals, which
are divided into signals based on heartbeat and those based on
respiration, on the basis of frequencies of the electric potential
signals. In other words, the planar electrode group described in
the publication had a high probability that, when normal electric
potential signals were not obtained from a seat occupant, signals
of both of heartbeat and respiration became not normal, which
lowered accuracy in wakefulness determination in some cases.
[0103] A vehicle seat Sa according to the second embodiment of the
present disclosure, is explained below. Firstly, the overall
structure of the vehicle seat Sa is explained with reference to
FIG. 12 and FIG. 13. In the explanation below, traveling direction
of a vehicle is referred to as forward direction, the opposite is
referred to as rearward direction, and vehicle height direction is
referred to as up to down direction.
[0104] Here, FIG. 12 is a perspective view showing an overall
structure of a vehicle seat Sa according to the second embodiment;
FIG. 13A is a schematic front view showing a seat back Sa2
comprising upper electrode units 11 constituting heartbeat sensors
10a; and FIG. 13B is a schematic plan view showing a seat cushion
Sa1 comprising rear-electrode units 8 and fore-electrode units 13
constituting the heartbeat sensors 10a, and a respiration sensor 9.
In an embodiment, in FIG. 12, FIG. 13 and FIG. 18 (described
below), locations of the respiration sensor 9, the heartbeat
sensors 10a, etc. are clearly shown by omitting some of parts
constituting the same (e.g., a leading wire 11d and a leading wire
8d). As shown in FIG. 12, the vehicle seat Sa comprises the seat
cushion Sa1 which is a portion on which a seat occupant is seated,
the seat back Sa2 which is a portion pivotally attached to a
rear-portion of the seat cushion Sa1, which corresponds to a
backrest of a seat occupant, and a wakefulness supporting device U
that support wakefulness of a seat occupant.
[0105] The seat back Sa2 has a cushion pad P2 made of urethane, and
a covering material Su2 provided in a manner covering the cushion
pad P2. As shown in FIG. 12 and FIG. 13A, in the seat back Sa2, the
upper electrode units 11 are also arranged in positions facing the
waist of a seat occupant.
[0106] The seat cushion Sa1 has a cushion pad P1 made of urethane,
and a covering material Su1 provided in a manner covering the
cushion pad P1. As shown in FIG. 12 and FIG. 13B, also arranged in
the seat cushion Sa1 are: the respiration sensor 9 and the
rear-electrode units 8 in positions facing the buttocks of a seat
occupant; and forward thereof, the fore-electrode units 13 in
positions facing the thighs of a seat occupant.
[0107] FIG. 12, FIG. 13B, etc. show a structure in which sensors
and electrode units such as the respiration sensor 9, the upper
electrode units 11, the rear-electrode units 8 and the
fore-electrode units 13 are arranged on a seating face. On the
other hand, it is also possible to arrange them between the cushion
pad P2 and the covering material Su2, or between the cushion pad P1
and the covering material Su1, to thereby obtain a desirable
appearance. The heartbeat sensor 10a comprising the rear-electrode
units 8, the fore-electrode units 13 and the upper electrode units
11; the respiration sensor 9; a detection device 21; a numerical
processing device 22; and a vibration device 23 form the
wakefulness supporting device U, and details thereof are explained
below.
Structure of Wakefulness Supporting Device
[0108] The wakefulness supporting device U is explained with
reference to FIG. 14 to FIG. 17, in addition to FIG. 12 and FIG.
13. Here, FIG. 14 is an enlarged view showing an upper electrode
unit 11; FIG. 15 is a view showing an XV-XV cross section of FIG.
14, which is a cross-sectional view of a portion of the upper
electrode unit 11; FIG. 16 is an enlarged view showing a
rear-electrode unit 8; and FIG. 17 is an enlarged view showing the
fore-electrode unit 13.
[0109] The wakefulness supporting device U is a device mainly
configured to support wakefulness of a seat occupant who mainly is
a driver, and comprised of the respiration sensor 9, the heartbeat
sensor 10a, the detection device 21, the numerical processing
device 22, and the vibration device 23.
[0110] The respiration sensor 9 is configured to detect a pressure
signal which is a signal indicating a level of consciousness which
fluctuates according to respiration of a seat occupant, and
comprises a publicly known pressure sensor. For example, the
respiration sensor 9 comprises a piezoelectric sensor-type pressure
sensor, a semiconductor piezoresistive-type pressure sensor, a
strain gauge-type pressure sensor, a capacitance-type pressure
sensor or a silicon resonant-type pressure sensor, or the like. The
respiration sensor 9 in the example of the present embodiment forms
a substantially M letter-shape, and arranged in the seat cushion
Sa1 such that the open side thereof faces rearward.
[0111] The heartbeat sensor 10a is configured to detect an
electrocardiographic signal which is an action potential signal
generated according to pulsation of a heart of a seat occupant, and
which is a signal indicating a level of consciousness. The
heartbeat sensor 10a is comprised of the upper electrode units 11
provided in a pair in the seat width direction of the seat back
Sa2, and the rear-electrode units 8 and the fore-electrode units 13
provided forward and rearward each in pairs in the seat width
direction of the seat cushion Sa1.
Upper Electrode Unit
[0112] The upper electrode unit 11 corresponds to a second
electrode unit, and as shown in FIG. 14, being formed into a sheet
state with a rectangular shape which is long generally in up to
down direction, having an area of about 100 cm2, and having a
capacitance of about 3000 pF. Further, the upper electrode unit 11
is mainly formed with a conductive sheet 11a, and is adhered onto
the cushion pad P2 of the seat back Sa2 with a double-sided tape
11ad that is adhered to the back face of the conductive sheet
11a.
[0113] As shown in FIG. 15, the conductive sheet 11a has a
laminated structure comprising a first resin film 11ac, a leading
wire 11d attached to the first resin film 11ac, a second resin film
11ab adhered to the first resin film 11ac in a manner sandwiching
the leading wire 11d, and an ink 11aa applied to the second resin
film 11ab. In the present embodiment, the first resin film 11ac is
formed with PET (Poly Ethylene Terephthalate).
[0114] A portion of the conductive sheet 11a including the leading
wire 11d formed with silver extends downward, protruding from the
rectangular shape, at a lower portion in the outer side in the seat
width direction of the upper electrode unit 11, with the end
portion thereof linked to a cable 11f by a terminal linking member
11e.
[0115] The terminal linking member 11e is formed with a metal
fragment having a suitable conductivity, and to one end thereof, an
end portion of the leading wire 11d is fastened, and to the other
end thereof, an end portion of the cable 11f is fastened. The cable
11f is then connected to the detection device 21 which is described
below. The second resin film 11ab is formed with a carbon resin,
and the ink 11aa is a metal ink comprising BaTiO.sub.3 (barium
titanate).
[0116] In the conductive sheet 11a, total six cuts 11b are formed,
each one in the center of the upper and lower edges, and each two
at a distance in the up to down direction in the left and right
edges, in the present embodiment. These cuts 11b are formed into a
semi-long hole shape having an arcuate edge. In addition, between
each pair of cuts 11b in the right to left direction formed on the
left and right edges of the conductive sheet 11a, each one long
hole-shaped cut out portion 11c is formed and extends longer than
the cuts 11b in the up to down direction. This cut out portion 11c
has both edges accurately shaped, and is formed into a long hole
shape. The leading wire 11d is arranged along the circumference of
the upper electrode unit 11, and extends inside the circumference
crosswise, spreading out in a manner linking the portions of four
corners of the leading wire 11d along the circumference and the
portions of the leading wire 11d along the cuts 11b. In particular,
towards the leading wire 11d along the cuts 11b formed on both
sides in the seat width direction, other two leading wires extend,
and these are arranged to be connected at different positions.
[0117] As described above, since the cuts 11b and the cut out
portions 11c are formed, a stress applied to the upper electrode
unit 11 as the covering material Su2 is bent is dispersed due to
the cuts 11b and cut out portions 11c. Since a stress is thus
dispersed, it is possible to inhibit the upper electrode unit 11
from being locally bent in an acute angle, and to prevent
generation of wrinkles in the upper electrode unit 11. Accordingly,
when the covering material Su2 is bent, the upper electrode unit 11
is bent along the covering material Su2, without causing wrinkles,
due to the cuts 11b and the cut out portions 11c, and therefore, it
is possible to control a stress from concentrating in one portion
of the leading wire 11d, and it is possible to prevent
disconnection of the leading wire 11d.
[0118] The leading wire 11d is spread out planarly crosswise in the
conductive sheet 11a, and at intersections thereof, two or less
leading wires 11d intersect, and three or more leading wires 11d do
not intersect. Since the number of leading wire 11d which
intersects at the intersections of the leading wires 11d is thus
limited to two or less, it is possible to dispose the leading wires
11d planarly in the conductive sheet 11a, and at the same time, to
make influence limitative when a disconnection has occurred.
Rear-Electrode Unit
[0119] The rear-electrode unit 8 corresponds to a second electrode
unit, and has a function of detecting a body electric potential of
a seat occupant, and as shown in FIG. 16, being formed into a sheet
state with a generally right-angled triangle shape, has an area of
about 40 cm2, and has a capacitance of about 1200 pF. The
rear-electrode unit 8 is mainly formed with a conductive sheet 8a
having a thickness and a laminated structure similar to those of
the conductive sheet 11a. The rear-electrode unit 8 is adhered onto
the cushion pad P1 of the seat cushion Sa1, with a double-sided
tape adhered to the back face of the conductive sheet 8a, similarly
as the upper electrode unit 11.
[0120] In an embodiment, a portion of the conductive sheet 8a
including the leading wire 8d extends inward in the seat width
direction, protruding from the right angled triangle shape, at a
rear portion in the inner side in the seat width direction of the
rear-electrode unit 8, with the end portion thereof linked to a
cable 8f by a terminal linking member 8e. Here, the terminal
linking member 8e and the cable 8f have similar constitutions with
those of the terminal linking member 11e and the cable 11f.
[0121] In an embodiment, the contact position of the seat cushion
Sa1 and the buttocks of a seat occupant is in an outer side in the
seat width direction compared to the contact position of the seat
back Sa2 and the waist of the seat occupant. To correspond to the
relationship of the contact positions, the rear-electrode unit 8
provided to the seat cushion Sa1 is provided at an outer side in
the seat width direction compared to the upper electrode unit 11
provided to the seat back Sa2. By thus arranging the upper
electrode unit 11 and the rear-electrode unit 8, it becomes
possible to obtain positions corresponding to contact portions of a
human body, to stabilize detection of cardiac electric potential
signals.
[0122] In the conductive sheet 8a, a cut portion 8b is formed in
the center of the edge in the fore-side, in the present embodiment.
This cut portion 8b is formed into a semi-long hole shape having an
arcuate edge. The leading wire 8d is arranged along the
circumference of the rear-electrode unit 8, and at the same time,
arranged to extend inside the circumference crosswise.
[0123] Since the cut portion 8b is formed in the conductive sheet
8a, when the covering material Su1 is bent, the rear-electrode unit
8 is bent along the covering material Su1, without causing
wrinkles, similarly as the conductive sheet 11a having the cut 11b.
Thus, it is possible to control a stress from concentrating in one
portion of the leading wire 8d, and it is possible to prevent
disconnection of the leading wire 8d.
[0124] Further, in the leading wire 8d, a number of leading wire 8d
which intersects at the intersections of the leading wire 8d is
limited to two, similarly as the leading wire 11d. In this manner,
it is possible to dispose the leading wire 8d planarly in the
conductive sheet 8a, and at the same time, to make influence
limitative when a disconnection has occurred.
[0125] The rear-electrode units 8 are disposed in a pair, in a
manner sandwiching the respiration sensor 9 in the seat width
direction. In other words, the rear-electrode units 8 are disposed
together with the respiration sensor 9, in a position facing the
buttocks of a seat occupant where contact stability is high. Since
the respiration sensor 9 is thus disposed in a position facing the
buttocks of a seat occupant, it becomes possible to stably detect a
respiration signal of a seat occupant, and since the rear-electrode
units 8 are disposed in a position facing the buttocks of a seat
occupant, it becomes possible to stably obtain a body electric
potential.
Fore-Electrode Unit
[0126] The fore-electrode unit 13 corresponding to a first
electrode unit is configured to function as a ground electrode unit
to be connected to a car body, and configured to obtain an electric
potential to be a reference potential in removing an offset signal
included in signals of the upper electrode unit 11 and the
rear-electrode unit 8. The fore-electrode unit 13 is formed into a
sheet state with a generally trapezoid shape, as shown in FIG. 17,
having an area of about 170 cm.sup.2, and having a capacitance of
about 5200 pF. The fore-electrode unit 13 is mainly formed with a
conductive sheet 13a having a thickness and a laminated structure
similar to those of the conductive sheet 8a. The fore-electrode
unit 13 is adhered onto the cushion pad P1 of the seat cushion Sa1,
with a double-sided tape adhered to the back face of the conductive
sheet 13a, similarly as the rear-electrode unit 8.
[0127] Then, the fore-electrode units 13 are provided in a straight
line in the fore-side of the rear-electrode units 8, in a position
facing the thighs of a seat occupant. In other words, since the
rear-electrode units 8 in the position facing the buttocks of a
seat occupant, and the fore-electrode units 13 facing the thighs of
the seat occupant are provided on the fore and rear straight lines,
it becomes possible to detect electrocardiographic signals of a
same type waveform transmitted linearly. By thus detecting
electrocardiographic signals of a same type waveform, it becomes
possible to detect a magnitude of an electrocardiographic signal,
and to distinguish physical condition of a seat occupant more
accurately.
[0128] In an embodiment, a portion of the conductive sheet 13a
including the leading wire 13d extends forward, protruding from the
trapezoid shape, at a fore-portion in the outer side in the seat
width direction of the fore-electrode unit 13, with the end portion
thereof linked to a cable 13f by a terminal linking member 13e.
Here, the terminal linking member 13e and the cable 13f have the
similar constitutions with those of the terminal linking member 11e
and the cable 11f.
[0129] In the conductive sheet 13a, total eight cut portions 13b
are formed, each one in the center of the upper and lower edges,
and each three at a distance in the up to down direction in the
left and right edges, in the present embodiment. In addition,
between each pair of cut portions 13b in the right to left
direction formed on the left and right edges in the back side of
the conductive sheet 13a, each one long hole-shaped cut out portion
13c is formed and extends longer than the cut portions 13b in the
front to back direction.
[0130] Similarly as the conductive sheet 11a having the cuts 11b
and the cut out portions 11c, a stress applied to the upper
electrode unit 13 as the covering material Su1 is bent is dispersed
due to the cut portions 13b and cut out portions 13c. Since a
stress is thus dispersed, it is possible to inhibit the
fore-electrode unit 13 from being locally bent in an acute angle,
and to prevent generation of wrinkles in the fore-electrode unit
13. When the covering material Su1 is bent, the fore-electrode unit
13 is bent along the covering material Su1, without causing
wrinkles, due to the cut portions 13b and the cut out portions 13c.
Thus, it is possible to control a stress from concentrating in one
portion of the leading wire 13d, and it is possible to prevent
disconnection of the leading wire 13d.
[0131] The leading wire 13d is arranged along the circumference of
the fore-electrode unit 13, and extends inside the circumference
crosswise, spreading out in a manner linking the portions of four
corners of the leading wire 13d along the circumference and the
portions of the leading wire 13d along the each two cut portions
13b in the back side.
[0132] At intersections of the leading wires 13d of plural numbers,
two leading wires 13d intersect, and three or more leading wires
13d do not intersect. Further, towards the leading wire 13d along
each two cut portions 13b in the back side, formed on both sides in
the seat width direction, other two leading wires extend, and these
are arranged to be connected at different positions. Since the
number of leading wire 13d which intersects at intersections of the
leading wires 13d of plural numbers is thus limited to two, it is
possible to dispose the leading wires 13d planarly on the
conductive sheet 13a, and at the same time, to make influence
limitative when a disconnection has occurred.
[0133] In the present embodiment, the rear-electrode units 8 and
the fore-electrode units 13 constituting the heartbeat sensor 10a
are arranged in the outer side in the seat width direction compared
to the respiration sensor 9. By being thus arranged, the
rear-electrode units 8 and the fore-electrode units 13 have outer
side positions in the seat width direction not limited by the
respiration sensor 9, and accordingly, it becomes possible to widen
the area of the heartbeat sensor 10a outward of the respiration
sensor 9. In addition, positions of the fore-electrode units 13 and
the respiration sensor 9 shifted from each other increase
probability that any of these sensors contacts with a seat
occupant, facilitating detection of body signals of a seat
occupant.
[0134] Furthermore, in the present embodiment, the upper electrode
units 11 and the respiration sensor 9 constituting the heartbeat
sensor 10a are arranged in positions overlapping with each other in
the seat width direction. Being thus arranged, it becomes possible
to share a portion which stably contacts with the body of a seat
occupant in the seat front to back direction, making it possible to
desirably detect a pressure signal and an electric potential
signal.
[0135] The above has been explained on a supposition that the body
electric potential is obtained at the rear-electrode unit 8, and
the fore-electrode units 13 is set as a ground electrode unit. This
is because, for detecting a body electric potential of the seat
occupant, it is desirable to arrange the rear-electrode unit 8 in a
portion corresponding to the buttocks of a seat occupant where it
is easy to maintain a contact. This is also because the
fore-electrode unit 13 provided in the seat cushion Sa1 is kept
apart from the heart of a seat occupant, which allows obtaining an
electric potential with a low influence of electrocardiographic
signal. However, the structure is not limited to the above, and may
also be such a structure where the rear-electrode unit 8 is set as
a ground electrode unit, and the fore-electrode unit 13 is set as
an electrode unit configured to detect a body electric potential.
It is also possible to separately provide a ground electrode unit
to the seat cushion Sa1, or to provide a ground electrode unit to
the seat back Sa2, to thereby obtain a body electric potential of a
seat occupant at least either at the rear-electrode unit 8 or at
the fore-electrode unit 13.
Detection Device, Numerical Processing Device, and Vibration
Device
[0136] As shown in FIG. 12, the detection device 21 is to detect a
biosignal relating to an electrocardiogram signal from electric
potential signals detected by the upper electrode unit 11 and the
rear-electrode unit 8, and a reference electric potential supplied
from the fore-electrode unit 13, and to detect a biosignal relating
to a respiration signal from a pressure signal obtained from the
respiration sensor 9; and formed with a ferrite core, a common mode
noise filter, an operational amplifier, etc. which are not
illustrated. The ferrite core and the common mode noise filter are
attached to a DC power line and have a function of removing a
conduction noise.
[0137] The numerical processing device 22 compares a respiration
signal and an electrocardiogram signal according a the biosignal
detected by the detection device 21 with individual predetermined
reference values, and when it is determined that a level of
wakefulness (level of consciousness or alertness) of a seat
occupant has lowered, transmits a driving signal to the vibration
device 23.
[0138] The vibration device 23 is a device provided with a
so-called "vibration motor" comprising a publicly known unbalance
mass motor, and drives the vibration motor for a predetermined time
according to a driving signal received from the numerical
processing device 22 to give a seat occupant a vibrational
stimulation. For example, the vibration device 23 is provided
inside the seat back Sa2.
[0139] Combinations of electrode units for comparing detected
electric potential signals in the heartbeat sensor 10a are now
explained. The numerical processing device 22 selects an arbitrary
two from six electrode units which are capacitance sensors, and
obtains electric potential signals of a seat occupant. Among the
six electrode units, an arbitrary one is set to be a ground
electrode unit. In an embodiment, the ground electrode unit may
separately be provided to an arbitrary position, for example, may
be provided between two capacitance sensors. This makes a favorable
contact condition of a ground electrode unit and an occupant, which
allows the ground electrode unit to stably supply a ground electric
potential. Since the numerical processing device 22 is capable of
processing a ground electric potential supplied from the ground
electrode unit and a signal obtained from the other electrode units
provided in the seat cushion Sa1 into a signal indicating a
consciousness level of a seat occupant, it becomes possible to
inhibit influence which accompanies a jolting of vehicle, a
difference in physique, and a posture, to allow a highly accurate
wakefulness determination.
[0140] The respiration sensor 9 provided in a rear side of the seat
cushion Sa1 which is a portion corresponding to the buttocks of a
seat occupant is capable of stably detecting a respiration signal,
similarly. Accordingly, the numerical processing device 22 uses
signals detected from the respiration sensor 9 and the heartbeat
sensor 10a in combination to determine a wakefulness condition of a
seat occupant, and thus it is possible to further enhance the
determination accuracy. In the above embodiment, the respiration
sensor 9 and the rear electrode unit 8 constituting the heartbeat
sensor 10a are provided in the seat cushion Sa1 where it is easy to
stably contact with a seat occupant. Therefore, it is possible to
inhibit an electric potential signal from a seat occupant from
becoming undetectable due to variation of contact position of a
seat occupant and the vehicle seat Sa that is caused by a
difference in physique, a posture, or the like of seat occupants.
By further providing the heartbeat sensor 10a to the vehicle seat
Sa separately from the respiration sensor 9, it becomes possible to
desirably obtain or select signals necessary to a wakefulness
determination, to enhance accuracy of a wakefulness
determination.
Another Embodiment
[0141] A seat cushion Sa3 according to another embodiment is
explained with reference to FIG. 18. Here, FIG. 18 is a schematic
plan view showing the seat cushion Sa3 provided with a
rear-electrode unit 16 and a fore-electrode unit 17 which consist a
heartbeat sensor 15, and a respiration sensor 14, according to the
another embodiment. In the present embodiment, with respect to
overlapping structures of the above embodiment, the same signs are
used and explanations thereof are omitted, in order to clarify
difference from the example described in the above embodiment.
[0142] In the seat cushion Sa3, as shown in FIG. 18, the
respiration sensor 14 and the rear-electrode units 16 which
correspond to the second electrode units are arranged in positions
facing the buttocks of a seat occupant, and forward thereof,
fore-electrode units 17 which correspond to the first electrode
units are arranged in a position facing the thighs of the seat
occupant.
[0143] While having the same constitution with the respiration
sensor 9, the respiration sensor 14 has a different shape from that
of the respiration sensor 9, and is provided to a position facing
the buttocks of a seat occupant. Specifically, the shape of the
respiration sensor 14 is a shape of a combination of a fore-portion
14a in a bent-state which is extended in the seat width direction,
a middle-portion 14b in a linear state which is extended in the
sheet front to back direction, intersecting with the center portion
of the fore-portion 14a, and a rear-portion 14c in a linear state
having the center connected to the rear end of the middle portion
14b, which is extended vertically to the middle-portion 14b.
[0144] While having the same constitution with the heartbeat sensor
10a, the heartbeat sensor 15 has a different shape from that of the
heartbeat sensor 10a. Specifically, a shape of a pair of the
rear-electrode unit 16 constituting a part of the heartbeat sensor
15 is a generally rectangular shape having a long portion in the
seat front to back direction, having a projecting portion 16d which
projects inward in the seat width direction in a part. The
projecting portion 16d corresponds to a protruding portion, and is
formed to project inward in the seat width direction, through the
fore-portion 14a to the rear-portion 14c of the respiration sensor
14 in the front to back direction.
[0145] Since the rear-electrode unit 16 thus comprises the
projecting portion 16d, it becomes possible to arrange the
respiration sensor 14, and the rear-electrode unit 16 of the
heartbeat sensor 15 in the vicinity of the ischial tuberosity
portion of a seat occupant where loads from the seat occupant are
applied the most. Here, the position in the vicinity of the ischial
tuberosity portion of a seat occupant refers to a position
specified by a dummy conforming to SAE standards. By arranging the
respiration sensor 14 and the heartbeat sensor 15 in this manner,
it becomes easy to share a point where loads from a seat occupant
are applied the most, between the heartbeat sensor 15 and the
respiration sensor 14. In this manner, it is possible to maintain
high accuracy in a detection of a signal detected from a seat
occupant, even when body movement is occurring due to jolting of a
vehicle, and to enhance accuracy of the wakefulness determination.
Since the respiration sensor 14 and the rear-electrode unit 16 of
the heartbeat sensor 15 are arranged in a position facing the
ischial tuberosity portion where pressure from a seat occupant is
the highest, it becomes possible to enhance a detection accuracy of
the respiration sensor 14 and the heartbeat sensor 15.
[0146] The respiratory sensor 14 and the rear electrode unit 16 of
the heartbeat sensor 15 according to the present embodiment are
arranged in the seat cushion Sa3 where buttocks are seldom moved
apart from the seat due to a body movement, even when buttocks are
lifted by jolting of vehicle, with which loads applied from the
buttocks fluctuate. This facilitates maintaining a contact of the
respiration sensor 14 and the heartbeat sensor 15 with a seat
occupant, to allow inhibiting occurrence of detection errors.
[0147] Furthermore, in the rear-electrode unit 16, a cut out
portion 16c in the center of the rectangular shape, and a cut
portion 16b in the fore-edge in the center of the rectangular shape
and in the proximal end side of the projecting portion 16d, are
formed similarly as in the rear-electrode unit 8. This cut portion
16b is formed into a semi-long hole state having an arcuate edge.
The cut out portion 16c is formed into a long hole state with the
both edges accurately shaped, and extends longer than the cut
portion 16b in the up to down direction. By forming the cut
portions 16b and the cut out portions 16c, a stress applied to the
rear-electrode unit 16 as the covering material Su1 is bent is
dispersed due to the cut portions 16b and the cut out portions 16c.
Since a stress is thus dispersed, it is possible to inhibit the
rear-electrode unit 16 from being locally bent in an acute angle,
and to prevent generation of wrinkles in the rear-electrode unit
16. Thus, it is possible to control a stress from concentrating in
one portion of a leading wire provided to the rear-electrode unit
16, to allow preventing disconnection of the leading wire.
[0148] A pair of fore-electrode unit 17 constituting a part of the
heartbeat sensor 15 corresponds to one of the first electrode
units, and disposed in the center portion in the front to back
direction of the seat cushion Sa3. Differently from the
fore-electrode unit 13, shape of the pair of fore-electrode unit 17
is formed such that a length in the front to back direction is
short and a length in the seat width direction is long. In the
fore-electrode units 17, each two cut out portions 17c extending in
the front to back direction are formed side by side in the seat
width direction, and cut portions 17b are formed in each
approximate center of both edges in the front to back direction and
in the seat width direction.
[0149] The fore-electrode unit 17 thus formed is provided to be
disposed over a wide region in a position close to root of the legs
of a seat occupant where less displacements occur, by being formed
longer than the fore-electrode unit 13 in the seat width direction,
in the center of the seat cushion Sa3. This increases chances of
the fore-electrode unit 17 to contact with a seat occupant, even in
such a condition that the seat occupant has the legs crossed, and
allows desirably applying a ground potential.
[0150] In addition, in the fore-electrode unit 17, each two cut out
portions 17c extending in the front to back direction are formed
side by side in the seat width direction, and cut portions 17b are
formed in each approximate center of both edges in the front to
back direction and in the seat width direction.
[0151] In this manner, when the covering material Su1 is bent, the
fore-electrode unit 17 is bent along the covering material Su1,
without causing wrinkles, similarly as the rear-electrode unit 16
having the cut portions 16b and the cut out portions 16c. Thus, it
is possible to control a stress from concentrating in one portion
of a leading wire provided to the fore-electrode unit 17, to allow
preventing disconnection of the leading wire.
[0152] The above has been explained on a supposition that the body
electric potential is obtained at the rear-electrode unit 16, and
the fore-electrode unit 17 is set as a ground electrode unit. This
is because, for detecting a body electric potential of a seat
occupant by the rear-electrode unit 16, it is desirable to arrange
the projecting portions 16d of the rear-electrode unit 16 in a
portion corresponding to the ischial tuberosity portion where it is
easy to maintain a contact with the seat occupant. However, the
structure is not limited to the above, and may also be such a
structure where the fore-electrode unit 17 is set as a ground
electrode unit, and the rear-electrode unit 16 is set as an
electrode unit configured to detect a cardiac electric
potential.
[0153] Although the above embodiment has been explained with taking
a vibration device as an example which forms the wakefulness
supporting device, the present disclosure is not limited to such
structure. For example, it is also possible to use a display, a
light, or a buzzer, or the like provided in a car to inform a seat
occupant or a fellow passenger with an image, a light, or a sound,
to directly or indirectly support wakefulness of the seat
occupant.
[0154] Furthermore, although the above embodiment has been
explained with taking a vehicle seat as an example, the present
disclosure is not limited to such structure, and is also applicable
to seats used in industrial equipment, airplanes, marine
applications, theaters or other applications.
Vehicle Seat Comprising Capacitance-Type Sensor According to Third
Embodiment of Present Disclosure
[0155] The vehicle seat according to the third embodiment of the
present disclosure relates to a vehicle seat comprising a
capacitance-type sensor capable of stably detecting a cardiac
electric potential of a seat occupant.
[0156] In order to promptly inform of a physical disorder of an
occupant of a vehicle, if occurred, structures for determining
physical disorder by detecting various parameters indicating a
condition of an occupant have been proposed. As a structure for
detecting a cardiac electric potential according to heartbeat of a
seat occupant who is an occupant of a vehicle, a structure in which
an electrode is provided inside a seat, in other words, on the back
side of a covering material has been known (e.g., the JP
2009-106673 Publication). In such a structure, an electric
potential detected by an electrode was lowered relative to a
thickness of a covering material, which lowered accuracy of a
heartbeat sensor, in some cases.
[0157] Techniques which have been known as a structure capable of
preventing such a lowering of electric potential are techniques of
conducting electricity from a covering material having suitable
conductivity to an electrode layer provided on the back face of the
covering material, through a conductive cloth (e.g., JP 2012-20002
Publication). However, in some cases, loads applied from a seat
occupant to the conductive cloth through the covering material
during operation broke through the conductive cloth over years of
use, which made an electric potential undetectable from the
electrode layer.
[0158] A vehicle seat Sb according to the third embodiment of the
present disclosure is described below. Firstly, the overall
structure of the vehicle seat Sb, and conductive cloths 31a, 31b
and 31e provided to the seat back Sb2 are explained with reference
to FIG. 19 to FIG. 21.
[0159] Here, FIG. 19 is a perspective view showing an overall
structure of the vehicle seat Sb according to the present
embodiment; FIG. 20 is a schematic front view showing the seat back
Sb2; and FIG. 21 is a view showing XXI-XXI cross section of FIG.
20, which is a side cross-sectional view of the seat back Sb2. As
shown in FIG. 19, the vehicle seat Sb has the seat cushion Sb1
which is a portion on which a seat occupant is seated, the seat
back Sb2 which is a portion attached to a rear-portion of the seat
cushion Sb1, which corresponds to a backrest of a seat occupant,
and a wakefulness supporting device U which supports wakefulness of
a seat occupant.
[0160] The seat back Sb2 has a cushion pad P2 made of urethane, and
a covering material Su2 provided in a manner covering the cushion
pad P2. The covering material Su2 is formed of a covering 40a and a
wadding 40b adhered to the back face of the covering 40a (see FIG.
21). On the seat back Sb2, a bank portions 39 formed in a manner
swelled forward are formed in the both sides in the seat width
direction. The seat back Sb2 is further provided with an upper
electrode unit 19a and a lower electrode unit 19b which form a
capacitance-type heartbeat sensor 18, in the center in the seat
width direction excluding the bank portion 39, on the back side of
the covering material Su2 between the cushion pad P2, as shown in
FIG. 21.
[0161] The upper electrode unit 19a and the lower electrode unit
19b are attached to the seat back Sb2 in such a direction that the
length in the seat width direction is shorter than the length in
seat up to down direction. Then, in the back face side of the
covering material Su2, conductive cloths 31a and 31b are connected
respectively to a short length portion of the upper electrode unit
19a and the lower electrode unit 19b. The conductive cloths 31a and
31b are attached to partially be exposed on the surface of the
covering material Su2, each formed to have a width of about 65 mm
and in a pair in the center of the seat width direction with a
center space of about 100 mm. The conductive cloths 31a and 31b
each provided in a pair are respectively connected to the upper
electrode unit 19a and the lower electrode unit 19b each provided
in a pair, and electricity is conducted therefrom.
[0162] As described above, since the conductive cloths 31a and 31b
are attached to the short portions of the upper electrode unit 19a
and the lower electrode unit 19b, less width of the conductive
cloths 31a and 31b can suffice the attachment to each of the
electrode units, compared to a case of being attached to the long
portions. As a result, the conductive cloths 31a and 31b can be
made more compact. Focusing on making the conductive cloths 31a and
31b further thin and compact, it is preferred that the conductive
cloths 31a and 31b be connected to the shortest edge of each of
detection faces of the upper electrode unit 19a and the lower
electrode unit 19b, respectively.
[0163] The seat back Sb2 is further provided with a conductive
cloth 31e which is connected to a not illustrated car body and
functions as a ground, between the cloth 31a and the cloth 31b in
the seat width direction, in the center of the seat back Sb2. The
conductive cloth 31e with a width of about 20 mm, extending from
the lower end of the seat back Sb2 to a higher position than the
conductive cloth 31b, is configured to obtain an electric potential
to be a reference electric potential in removing an offset signal
included in a signal from the upper electrode unit 19a and the
lower electrode unit 19b.
[0164] The seat cushion Sb1 comprises a cushion pad P1 made of
urethane, and a covering material Su1 provided in a manner covering
the cushion pad P1. The seat cushion Sb1 is further provided inside
with the upper electrode unit 19a, the lower electrode unit 19b,
and the detection device 21 and the numerical processing device 22
which, together with the vibration device (not shown), form the
wakefulness supporting device U. The detection device 21 is
configured to detect a biosignal according to an
electrocardiographic signal from an electric potential signal
detected by the upper electrode unit 19a and the lower electrode
unit 19b, and formed from a ferrite core, a common mode noise
filter, an operational amplifier, etc. which are not illustrated.
The ferrite core and the common mode noise filter are attached to a
DC power line and have a function of removing a conduction noise.
The numerical processing device 22 separates electrocardiographic
signals from a biosignal detected by the detection device 21, which
is compared with the individual predetermined reference values, and
when it is determined that a level of wakefulness (level of
consciousness) of a seat occupant has lowered, transmits a driving
signal to a not illustrated vibration device. Then, the vibration
device gives a seat occupant a vibrational stimulation to support
wakefulness condition of the seat occupant.
[0165] Next, functions of the conductive cloth 31a and the
conductive cloth 31b, and attachment of the conductive cloth 31a
and the conductive cloth 31b to the covering material Su2 are
explained. The conductive cloth 31a is connected to the upper
electrode unit 19a, and the conductive cloth 31b is connected to
the lower electrode unit 19b. Accordingly, a cardiac electric
potential of a seat occupant is detected by the upper electrode
unit 19a and the lower electrode unit 19b, without causing lowering
of electric potential due to passing through the covering material
Su2. Then the electric potentials detected by the upper electrode
unit 19a and the lower electrode unit 19b are transmitted to the
detection device 21 through a cable 19f.
[0166] The cushion pad P2 is divided into an upper pad 38a, a
middle pad 38b and a lower pad 38c with a hanging groove 45a, in
the center of the seat width direction of the seat back Sb2
excluding the bank portion 39. Here, the hanging groove 45a
corresponds to a "portion extending in the seat width direction".
Similarly, among the covering materials Su2 provided to the seat
back Sb2, the covering material Su2 in the center of the seat width
direction is configured to be divided from up to down into three of
an upper covering material 37a, a middle covering material 37b, and
a lower covering material 37c, covering the upper pad 38a, the
middle pad 38b and the lower pad 38c, respectively.
[0167] The upper covering material 37a, the middle covering
material 37b and the lower covering material 37c are attached with
the end portions thereof taken in the hanging groove 45a provided
to the cushion pad P2. Specifically, a wire 43 suspended in the
seat width direction is attached inside the hanging groove 45a. A
hook 44 in a J-letter shape attached to this wire 43 is engaged
with a suture portion 42b in the terminal of the covering material
Su2 to thereby attach the covering material Su2 to the seat back
Sb2.
[0168] The conductive cloth 31a is formed into a belt-state in a
manner extending long in the seat height direction, and comprises a
turnover portion 35a which is turned over straddling the lower side
terminal of the middle covering material 37b on the front face and
the back face of the middle covering material 37b, at the position
where it is attached to the hanging groove 45a. The turnover
portion 35a of the conductive cloth 31a is sutured at the suture
portion 42b together with the lower side terminal of the middle
covering material 37b and the upper side terminal of the lower
covering material 37c, and fixed to the seat back Sb2 by the hook
44 corresponding to a hanging portion. Since the turnover portion
35a where a partial positional deviation with the covering material
Su2 tends to occur is fixed by the hook 44, it is possible to
desirably prevent the positional deviation of the conductive cloth
31a. Further, the upper side terminals of the conductive cloth 31a
in the both sides sandwiching the front and back faces of the
middle covering material 37b are also sutured to the middle
covering material 37b by a suture portion 42a.
[0169] The conductive cloth 31b is formed into a belt-state in a
manner extending long in the seat height direction, and comprises a
turnover portion 35b which is turned over straddling a terminal of
the lower covering material 37c on the front face and the back face
of the lower covering material 37c at the lower end portion of the
seat back Sb2. Here, the lower end portion of the seat back Sb2
corresponds to a "portion extending in the seat width direction".
The upper side terminals of the conductive cloth 31b in the both
sides sandwiching the front and back faces of the lower covering
material 37c are sutured to the lower covering material 37c by the
suture portion 42a. In this manner, the conductive cloths 31a and
31b are attached to be turned over at the hanging groove 45a
extending in the seat width direction and at the lower end portion
of the seat back Sb2. Thus, the turnover portion 35a of the
conductive cloth 31a and the turnover portion 35b of the conductive
cloth 31b are difficult to be brought into contact with a seat
occupant, and little tension in the seat width direction is applied
thereto, and accordingly, it is possible to inhibit disconnection
of leading wire in the conductive cloths 31a and 31b. Thus, the
conductive cloths 31a and 31b are stably attached to the seat back
Sb2.
[0170] By arranging the turnover portions 35a and 35b with avoiding
the side face in the seat width direction of the vehicle seat Sb
where a tensile load is significantly applied by a seat occupant
leaning thereover, it is also possible to decrease a tensile load
applied to the turnover portions 35a and 35b. In particular, since
the turnover portions 35a and 35b are provided in the center side
of the seat width direction excluding the bank portion 39, it is
possible to decrease a tensile load applied to the turnover
portions 35a and 35b to be extremely small, even when a seat
occupant abuts the bank portion 39 due to a lateral jolting of a
vehicle. In this manner, it is possible to stably maintain a
condition of attachment of the conductive cloth 31a and the
conductive cloth 31b to the seat back Sb2, and to inhibit
disconnection of the leading wire inside the conductive cloths 31a
and 31b, allowing stable detection of a cardiac electric potential
of a seat occupant.
[0171] Although, in the above embodiment, a structure in which
conductive cloths are arranged in a seat back has been explained,
the present disclosure is not limited to such structure, but is
also applicable to a structure in which a conductive cloth is
arranged in a seat cushion. Although, in the above embodiment,
conductive cloths have been explained, it is possible to use any
metal conductive body having a suitable conductivity capable of
conducting electricity to an electrode, and it is possible to use a
conductive fiber sewed into the covering material. Number of the
electrode, number of the hanging groove, number of the conductive
cloth, etc. in the embodiments are arbitrary, depending on a seat
shape.
[0172] Although the above embodiment is explained with taking a
vibration device as an example which forms the wakefulness
supporting device, the present disclosure is not limited to such
structure. For example, it is also possible to use a display, a
light, or a buzzer, or the like provided in a car to inform a seat
occupant or a fellow passenger with an image, a light, or a sound,
to directly or indirectly support wakefulness of the seat
occupant.
TABLE-US-00001 TABLE OF REFERENCE NUMERALS 1: Pressure sensor
(Detector) 2: ECU (Signal receiving portion) 3: Leading wire (First
transmission path forming portion) 4: Cable (Second transmission
path forming portion) 5: Terminal linking member (Fastening member)
6: Holder film 6A: Sensor attachment portion 6B: Middle portion
(Second portion) 6C: Expanded portion (First portion) 6m: First
extending portion 6n: Second extending portion 7: Insulating tape
8: Rear-electrode unit (Second electrode unit) 8a: Conductive sheet
8b: Cut portion 8d: Leading wire 8e: Terminal linking member 8f:
Cable 9: Respiration sensor 10: Sensor unit 10a: Heartbeat sensor
11: Upper electrode unit (Second electrode unit) 11a: Conductive
sheet 11aa: Ink 11ab: Second resin film 11ac: First resin film
11ad: Double-sided tape 11b: Cut 11c: Cut out portion 11d: Leading
wire 11e: Terminal linking member 11f: Cable 12: Warp restraining
member 12a: Outer surface 12b: Flange portion 12c: Recess portion
13: Fore-electrode unit (First electrode unit) 13a: Conductive
sheet 13b: Cut portion 13c: Cut out portion 13d: Leading wire 13e:
Terminal linking member 13f: Cable 14: Respiration sensor 14a:
Fore-portion 14b: Middle portion 14c: Rear-portion 15: Heartbeat
sensor 16: Rear-electrode unit (Second electrode unit) 16b: Cut
portion 16c: Cut out portion 16d: Projecting portion (Protruding
portion) 17: Fore-electrode unit (First electrode unit) 17b: Cut
portion 17c: Cut out portion 18: Heartbeat sensor 19a: Upper
electrode unit 19b: Lower electrode unit 19f: Cable 20: Through
hole 20a: Gradient face 21: Detection device 22: Numerical
processing device 23: Vibration device 31a, 31b, 31e: Conductive
cloth 35a, 35b: Turnover portion 37a: Upper covering material 37b:
Middle covering material 37c: Lower covering material 38a: Upper
pad 38b: Middle pad 38c: Lower pad 39: Bank portion 40a: Covering
40b: Wadding 42a, 42b: Suture portion 43: Wire 44: Hook (Hanging
portion) 45a: Hanging groove C1: Administrative chair (Seat with
detector) P: Pad member P1: Cushion pad P2: Cushion pad Pa: Hanging
groove S: Present seat (Seat with detector) S1: Seat cushion S2:
Seat back S3: Headrest Sa: Vehicle seat Sa1, Sa3: Seat cushion Sa2:
Seat back Sb: Vehicle seat Sb1: Seat cushion Sb2: Seat back Su1,
Su2: Covering material (Seat covering) T: Adhesive tape U:
Wakefulness supporting device
* * * * *